World No. 30 Barbora Krejcikova of the Czech Republic masterminded the biggest upset of the Dubai Duty Free Tennis Championship, stunning Australian Open champion and second seed Aryna Sabalenka of Belarus 0-6, 7-6, 6-1 on Thursday.

She will meet Jessica Pegula of the United States in the semifinal. Pegula received a Karolina Muchova of Czech Republic, who suffered an abdominal injury.

Sabalenka came into the WTA 1000 tournament as one of the hot favourites, as her 13-match win streak lent her an aura of invincibility. The escape act against the defending champion Jelena Ostapenko of Latvia in the Round of 16 only served to burnish her reputation.

There were no early jitters on Thursday as she hurried to wrap up the first set in 29 minutes without conceding a set. The pattern continued in the second, with Sabalenka firing winners on either flank with power and precision.

The turnaround

Krejcikova was staring down the barrel when the Czech was a set down and 1-3 in the second set. From there, the World No. 30 masterminded the biggest upset of the tournament.

Initially, she was content to keep the ball playing before finding ways to beat the flailing racquet of Sabalenka. She broke back and pushed the set into the tiebreaker, which she won 7-2.

By then, the wind seemed to have gone out of Sabalenka’s sails more, and more errors crept into her game. Krejcikova broke Sabalenka in the fourth and sixth games to run up a 5-1. The Belarusian saved two match points, but it was too far a bridge to cross.

Looking back at the match, Krejcikova said: “I was just fighting. There’s not much you can change because she [Sabalenka} plays well, serves well, and hits really hard. I was just trying to get to her pace; just try to be a little more aggressive because otherwise, it’s difficult.”